Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to improvement of call performance during poor or changing radio conditions and/or severe changes in radio conditions.
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (WCDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
Currently, in a soft hand off mode, a Change of best cell procedure may be triggered by a user equipment (UE) using an Event 1D measurement request indicating that a target cell has performed better than a serving cell for approximately a Time-To-Trigger (TTT) duration as per the equation given in 3GPP 25.331 RRC Protocol Specification sub-clause 14.1.2.4 “Reporting Event 1D: Change of best cell.” Where a cell is small and/or a network configured TTT is large, the UE might not be able to communicate with the serving cell by the time TTT has expired. As such, an Event 1D measurement may not be triggered and/or transmitted to the serving cell. Further, even where the Event 1D message is able to be transmitted to serving cell, the UE may lose its connection with the serving cell thereafter and may not be able to complete the Change of Best Cell procedure successfully and completely.
Thus, improved apparatus and methods for call performance during poor or quickly changing radio conditions and/or severe changes in radio conditions may be desired.